Nacreous glass flake pigment compositions

Claim 1

A PIGMENT COMPOSITION CONSISTING ESSENTIALLY OF GLASS FLAKES HAVING A SPECIFIC SURFACE OF LESS THAN 1 M.2/G., A THICKNESS OF 1.0 TO 5.0 MICRONS, AND THE MAJOR DIMENSION OF THE PARTICLES OF SAID FLAKES RANGING FROM ABOUT 10-400 MICRONS, WITH AT LEAST 50% BEING BELOW 75 MICRONS AND ABOUT 85% BEING BELOW 150 MICRONS, SAID FLAKES HAVING A NUCLEATING SURFACE CONSISTING OF 0.2-50%, BASED ON THE WEIGHT OF SAID FLAKES, OF DEPOSITED FINELY DIVIDED COLLOIDAL, BELOW 50 MILLIMICRON, PARTICLES OF AN ACID INSOLUBLE METAL OXIDE COMPOUND SELECTED FROM THE GROUP CONSISTING OF TIN OXIDE AND FIBROUS BOEHMITE ALUMINA DEPOSITED DIRECTLY ON SAID GLASS FLAKES, UPON WHICH SURFACE IS SUPERIMPOSED A THIN, ADHERENT COATING OF AN OUTER TRANSLUCENT LAYER OF METAL OXIDE PARTICLES SELECTED FROM TEH GROUP CONSISTING OF TITANIUM DIOXIDE, ZIRCONIUM DIOXIDE, CHROMIUM OXIDE, IRON OXIDE, NICKEL OXIDE, COBALT OXIDE, TIN OXIDE AND HYDROUS FORMS THEROF, SAID LAYER RANGING IN THICKNESS FROM ABOUT 20 MILLIMICRONS TO ABOUT 250 MILLIMICRONS WITH THE PARTICLES THEREOF BEING LESS THAN 0.1 MICRON SIZE AND COMPOSITION BEING A COLORED, NACREOUS FLAKE PIGMENT EXHIBITING, UNDER BRIGHT ILLUMINATION, A LUSTROUS SPARKLE WITH A PREDOMINANT COLOR VARYING WITH INCREASING THICKNESS OF THE OUTER TRANSLUCENT LAYER.